Dill weed is scientifically known as Anethum graveolens and part of the same family as parsley, cumin and bay leaf. It's native to the Mediterranean region and has been used since ancient Greek and Roman times as both a spice and a medicine. It's a good source of calcium, manganese and iron and also contains flavonoids, known for their antioxidant, anti-inflammatory and antiviral properties.
Dill has been investigated for its various antimicrobial effects, including one study published in the "Journal of Food Science" in 2006 that showed the essential oil of dill weed was effective against several bacteria strains, completely inhibiting the growth of Fusarium graminearum, as well as being toxic to five other bacteria, including Staphylococcus aureus. Another study at the University of Vienna found that dill extracts taken from seeds stored for 35 years also killed several fungal strains such as the mold Aspergillus niger and the yeasts Saccharomyces cerevisiae and Candida albicans.
Dill weed leaf extract was given to rats for 14 days at Iran's Institute of Biochemistry and Biophysics, reducing their triacylglyceride levels by up to 50 percent and total cholesterol by 20 percent. A separate study in Iran in 2008 found that daily oral administration of dill extract to rats at doses of 45, 90 and 180 milligrams per kilogram of body weight for two weeks significantly reduced total cholesterol, triglyceride and low density lipoprotein cholesterol, showing its promise as a heart-protective agent.
Dill weed may be effective in helping diabetics regulate insulin levels, although studies to date have only been performed on laboratory animals. But Indian researchers found that rats receiving dill leaf extract for 15 days had a decrease in the concentration of both serum glucose and insulin, indicating the herb's potential to regulate corticosteroid-induced diabetes.
Dill weed has been used as a digestive aid in many cultures, due to its antispasmodic properties that relieve cramping and stomach pain. In a study published in "BMC Pharmacology" in 2002, dill weed was also shown to significantly inhibit acid secretion and the development of stomach lesions, providing a level of anti-ulcer activity in laboratory mice.
Another traditional use for dill weed has been to regulate the menstrual cycle in women. One Iranian study in 2006 found that rats fed high doses of dill extracts had measurably longer estrous cycles and increased blood progesterone concentrations, leading the scientists to conclude that dill can be used either to help stabilize irregular cycles in women or as an antifertility agent, due to the progesterone effects.
Dill contains monoterpene effects, which ultimately help anti-oxidant molecules attach to oxidized molecules that would otherwise do damage in the body. These effects were confirmed in a multinational study published in the "Journal of Food Science" in 2006, as well as research at the Tehran University of Medical Sciences two years earlier showing that the antioxidant activity of dill is comparable to ascorbic acid, alpha-tocopherol and quercetin in vitro.